Apparatus for applying the enveloping fabric to raw transmission belts

ABSTRACT

The present invention relates to an apparatus for applying the enveloping fabric to raw transmission belts, which apparatus is provided with spaced pulleys receiving the raw tire and with profiled rollers distributed over the cross-sectional circumference of the raw belt for folding and pressing the enveloping fabric against the raw belt. The invention is characterized primarily in that the drive of the pulleys is coupled to a control member which acts upon limit switches for releasing working operations while said control member is under the continuous load of a return force acting counter to the driving force.

States Patent In en or Krause, Martin; Fiirsterling, Klaus and Walter K'zise, all of Hannover, Germany Appl. No 673,845 Filed Oct. 9, 1967 Patented Oct. 26, 1971 Assignee Continental Gummi-Werke Aktiengesellschaft Hannover, Germany Priority Oct. 11, 1966 Germany C 40338 APPARATUS FOR APPLYING THE ENVELOPING FABRIC TO RAW TRANSMISSION BELTS [56] References Cited U ,N1TED STATES PATENTS 3,322,604 5/1967 Schott, Jr. 156/583 2,529,859 11/1950 Ambler et al. 156/460 3,291,674 12/1966 Worrall, Jr. et al .4 156/460 X Primary Examiner-Benjamin A. Borchelt Assistant Examiner-Jerald J. Devitt Attorney-Walter Becker ABSTRACT: The present invention rel/ates to an apparatus for applying the enveloping fabric to raw transmission belts, which apparatus is provided with spaced pulleys receiving the raw tire and with profiled rollers distributed over the crosssectional circumference of the raw belt for folding and pressing the enveloping fabric against the raw belt. The invention is characterized primarily in that the drive of the pulleys is coupled to a control member which acts upon limit switches for releasing working operations while said control member is under the continuous load of a return force acting counter to the driving force.

AlPlPAlltAT US FOR APPLYING Tl-IE ENVELOPTNG FABRIC T RAW TRANSMISSION BELTS The present invention relates to an apparatus for applying the enveloping fabric to raw transmission belts which apparatus comprises driven pulleys distributed over the crosssectional circumference of the raw belts passed over said pulleys which are variable as to their spacing, said apparatus also comprising rotatably journaled profile rollers for folding and pressing the enveloping fabric against the respective belt which fabric is fed in the form of a band or web.

Heretofore known wrapping machines of the above-mentioned type require an unusual amount of manual work. The fabric is fed by hand, stretched and cut by hand while the drive of the pulleys has to be controlled by foot-operable pedals or the like in conformity with the requirements. The quality of the work, therefore, depends to a great extent on the skill and attention of the operator, and irregularities and lack of precision are unavoidable. The actuation of the foot pedal frequently causes an early tiring of the operator who has to stand up all the time which fact may even affect the health of the operator. The physical requirements to be met by an operator and the drawbacks resulting therefrom also relatively frequently cause interruption of the work.

lt is, therefore, an object of the present invention to provide an apparatus for applying the wrapping to raw transmission belts, which will overcome the above-mentioned drawbacks.

lt is a further object of this invention to provide an apparatus of the above-mentioned type which will considerably reduce the heretofore necessary manual work.

These and other objects and advantages of the invention will appear more clearly from the following specification in connection with the accompanying drawing which diagrammatically illustrates an envelope applying machine for V-belts.

An apparatus as set forth above is, in conformity with the present invention, characterized primarily in that the drive of the pulleys is coupled with a control member which acts upon limit switches for initiating working operations, said control member being under the load of a returning force which acts in the direction opposite to the driving force. The control member is advantageously through the intervention of a stepdown transmission and a detachable clutch which is ineffective when the drive is disconnected, operatively connected to the driving motor for the pulleys. Such clutch may, for instance, be an electromagnetically operated clutch. The distance between the limit switches and the control member in rest position may be variable.

In case the apparatus according to the present invention is equipped with a tensioning device, for instance in the form of a pressure-fluid-operable working cylinder with a piston rod supporting the bearing of a pulley, and when said tensioning device becomes effective so as to increase the distance between the pulleys, it is possible according to a further development of the invention to connect the piston rod of the working cylinder with toggle joints which determine the rest position of the control member. In this way a positive dependency of the control member play from the circumferential length of the respective raw belt on the pulley is established so that deviations in measurement for a certain belt size will automatically be compensated for within an adjustable tolerance range.

According to a further feature of the present invention, there are ahead of the pulleys provided a guiding device for the oncoming enveloping web which device is longitudinally displaceable with regard to said pulleys, and a cutting knife arranged at an incline with regard to the edges of the enveloping web or fabric, said cutting knife being under the influence of a pressure-fluid-operable cylinder-piston system. The guiding device is advantageously formed by two freely rotatable guiding rollers receiving the enveloping web or textile fabric therebetween so that it will be possible with relatively simple means by exerting a braking force upon one ofthe guiding rollers over an adjustable period of time to subject said enveloping web to a pulling stress and to cause said web sectionwise at reduced width to pass onto the raw lbelt. This possibility is desired for a multiple wrapping in which case the lower fabric layer is applied in stretched condition: at a lower width than the outer fabric layer.

Referring now to the drawing in detail, the apparatus illustrated therein comprises four processing stations which differ from each other according to their functions and which have been shown delimited in the drawing by dot-dash lines, said stations being designated I, ll, Ill and IV respectively. More specifically, l designates the textile-withdrawing station; ll indicates the fabric or textile-feeding station with cutting knife; lll designates the folding roller head; and W comprises the tensioning device with setting or control member and lengthcompensating mechanism.

The fabric or textile-withdrawing station l comprises the textile web 3 which has been wound into a roll l while between the windings of the roll there is interposed a foil, a follower web or a textile 2. By means. of a winding motor 4 with variable speed transmission, the follower web is withdrawn in the direction of the arrow A and is wound upon a spool 5, whereas the enveloping web 3 is passed over stationarily located deviating rollers 15 and conveyed to the succeeding stations. Roller 7 is located at one end of a rocker 9 supported by a stationary support 8, said rocker being adapted to be placed under load by a displaceable weight 10 in a variable manner. This arrangement makes it possible to preload the textile web 3 according to the respective requirements and to adapt the guiding of the textile web to varying conditions of operation.

The feeding station ll for feeding the textile web comprises as most important parts two guiding rollers 11 and R2 between which the textile web 3 is passed which comes from a stationary deviating roller M. The guiding rollers are freely rotatably journaled for rotation in the direction of the arrows B and C respectively, whereas by means of a freewheel clutch they are prevented from rotating in opposite direction whereby a backsliding of the textile web is prevented. The rollers are frictionally turned by the moving web in the direction of the arrow B and C respectively. By pressing a friction member 15 by means of a working cylinder 16 against the lower guiding roller ll2, it is possible to exert a retarding braking force upon the textile web. Frame 13 is slidably guided and is operatively connected to a cylinder-piston system l7 adapted to reciprocate said frame 13 in the plane of movement of the textile web 3 in the direction of the arrows 13a. The guiding rollers l1 and R2 are followed by a separating knife 18 with a cutting blade which is inclined with regard to the longitudinal edges of the textile web, said cutting blade extending over the entire width of the web. The separating knife 18 is arranged at the free end of an angle lever 20 pivotable at 19 and linked to the piston rod of a cylinder-piston system 21, said angle lever 20 being adapted to be pivoted by said cylinder-piston system 21. The separating knife is together with a pad pertaining thereto arranged on a common base plate 23. The base plate 23 in its turn is mounted on a rotatable stud 24 and through a linkage 25 is pivotally connected with the frame 13 in such a way that said base plate at the approach of said frame 13 is turned out of the drawing plane by an angle of approximately The folding roller head lll comprises a set of stationary profile rollers 26 and a set of profile rollers 27 displace-able relative to said profile rollers 26. The profile rollers are designed in a manner known per se and have their outer circumference so designed that in cooperation with each other they fold the textile web 3 coming from the feeding station ll around the raw belt 28 which is guided on pulleys 29, 30 of the same size. The profile rollers then press. the textile web 3 over its entire cross-sectional circumference against the raw belt. Whereas the stationarily located profile rollers 26 are arranged directly at the inner circumference of the raw belt and are able elastically to yield only within narrow limits. the counter rollers 27 are combined in a common roller support and together with the latter are mounted on the piston rod of a working cylinder-piston system 31 so that in an alternating working cycle they are moved toward or away from the raw tire and under the effect of the working cylinder 31 can be pressed against the raw tire.

The tensioning device IV comprises the two pulleys 29, 30. The pulley 29 is journaled about a stationary pivot and is driven by a motor 32. The bearing for the pulley 30 on the other hand is located on the forked piston rod of a working cylinder 33. By corresponding actuation of the cylinder piston system 33, the radial distance of the two pulleys 29, 30 can be reduced for mounting and withdrawing the raw belt 28, whereas for purposes of tensioning said raw belt, said radial distance can be increased during the rotation of the belt about the pulleys. For purposes of simply adjusting the arrangement for different belt lengths, the cylinder-piston system 33 is longitudinally displaceable and may with the aid of an adjusting screw 35 by means of a handwheel be moved to a starting position which is closer to or farther away from the pulley 29.

A rotatable adjusting member in the form of a control lever 37 is coupled to the driven pulley 29 through the intervention of a slip-free toothed belt or chain drive 29a, said control lever 37 being rotatable in front of an indexing disc 36. Inserted into the drive of the control lever is an electrodisc clutch 38 indicated by dash lines which clutch becomes effective only when the driving motor 32 is engaged, whereas it will interrupt the power flow when the motor is disengaged in order to permit the control lever 37 to return to its zero position under the influence of a weight 39 which is suspended on its turning shaft and is lifted in the driving phase. By means of a nonillustrated stepdown transmission, the tilting movement of the control lever 37 may be so tuned to the speed of the pulleys that the complete circumference of the raw belt 28 has associated therewith an arc of less than 360 on the indexing disc 36. The zero position of the control lever is determined by a pushrod 40 acting as abutment and operatively connected through a linkage 41 with the piston rod of the working cylinder-piston system 33. Within the tilting range of the control lever there are provided limit switches 42 and 43 which are so arranged that they can be actuated during the course of a movement of lever 37. The limit switch 42 which is reached after a movement through 90 controls the actuation of the braking cylinder 16, whereas for instance the limit switch 43 on the 180 mark is inserted into the circuit of the driving motor and of the clutch 38.

The operation of the apparatus is as follows. A raw belt 28 is placed upon the pulleys 29, 30 whereupon by venting the working cylinder 33 and moving away of the pulley 30 the raw tire 28 is tensioned and brought into the range of action of the profile rollers 26. Simultaneously with the tensioning cylinder 33 also the feeding cylinder 17 is actuated. The necessary control operations can be initiated with any known means by actuating a single-key valve. The frame 13 which advances under the effect of the feeding cylinder 14 will in view of the guiding rollers ll, 12 locked against a rearward rotation take along the textile web 3 and move the web end which previously was trimmed by the separating knife 18 into contact with the raw belt moving away from the pulley 29. In its end position, the frame 13 actuates a valve (not shown) which controls the passage of compressed air into the working cylinder-piston system 31. While the frame subsequently returns to its illustrated normal position in which also the separating knife is tilted back into the drawing plane, the cylinder-piston system 31 lifts the profile rollers 27 into their working position while simultaneously by engaging a nonillustrated switch the braking cylinder 16 is vented and the friction member is pressed against the guiding roller 12. The actuation of the braking cylinder by fluid pressure serves as initiating impulse for closing the circuits for the driving motor 32 and for the electrodisc clutch 38 whereupon the wrapping process proper starts.

The textile web 3 is grasped by a profile roller 44 which is resiliently journaled and precedes the profile rollers 27 whereupon the textile web in cooperation with the pulleys 29 is passed between the profile rollers 26, 27 where, free from folds, it will engage the entire cross-sectional circumference of the raw belt. In view of the braking effect exerted upon the guiding roller 12, the web 3 will be under a certain tensioning stress and therefore will move to the first wrapping phase with a reduced width. As soon as after applying the first enveloping layer, the control lever 37 passes over the limit switch 42, the venting of the braking cylinder 16 is interrupted, and the second wrapping layer is subsequently applied without stretching. Shortly prior to the completion of the second belt circulation, the control lever reaches the limit switch 43 which turns off the entire drive including the clutch 38 and at the same time initiates the supply of actuating fluid to the working cylinder system 21 associated with the separating knife 18. While the weight 39 returns the control lever 37 to its zero position, the downwardly moving separating knife 18 cuts off the textile web 3 and thus releases the impulse for withdrawing the end piece. The driving motor 32 is through the intervention of a timer engaged once more in order to complete the wrapping operation. Subsequently, the working cylinder piston 35 moves in the direction toward the stationary pulley 29 whereupon the finish wrapped raw belt can be removed.

As will be evident from the above, the present invention makes it possible that all of the working operations inherent to the wrapping of the raw belts can be carried out automatically. The work of the operator will be limited merely to the placing of the belts upon the pulleys and to the withdrawing of the finish wrapped belts. The elimination of any further manual work will exclude errors of operation and will assure optimum work quality with a high uniformity over large numbers of series. The improvement manifests itself particularly in the way in which the overlapping portion of the enveloping web is effected. Whereas the manually superimposed textile web ends have differently long overlapping zones and therefore on the finished belt frequently lead to undesired unbalance or also form the cause of waste, with the apparatus according to the present invention, the critical overlapping area for all belts will show always a uniform adjustable appearance so that the belt in use will have the highest possible quiet movement. In addition to the improvements of the end product, the present invention also from an operational standpoint and with regard to the operator has considerable advantages. The considerably simplified operation of the wrapping machine according to the invention will considerably reduce the required training time will also make possible changes in personnel without affecting the output quality. Since the working steps are effected in automatic sequence, and since an operator controlled handling of the foot pedal or a manual interference is not required, even over a longer working period the operator is not subjected to any physical strain with the harmful results inherent thereto which in turn also reduces any danger of accidents due to fatigue.

It is, of course, to be understood that the present invention is, by no means, limited to the particular arrangement shown in the drawing but also comprises any modifications within the scope of the appended claims.

What we claim is:

1. An apparatus for applying the enveloping fabric to a raw transmission belt which includes in combination spaced pulleys adjustable relative to each other for receiving and rotating the raw belt to be wrapped, profiled rollers rotatably journaled and distributed around the path over which the raw belt moves from one pulley to the other pulley for folding and pressing an enveloping belt against and around a raw belt, driving means operatively connected to said pulleys to drive the same, movable control means coupled to said driving means, limit switch means arranged within the range of movement of said control means and operable by the latter to initiate working operations in said apparatus, means for continuously urging said control lever means automatically and positively to return to its starting position, stepdown transmission means, a releasable clutch, said control means being connected to said pulle driving means through said stepdown transmission and said clutch, electromagnetic means for making said clutch ineffective in response to disengaging said driving means, said limit switch means being arranged movably at a variable distance from said control means when the latter is in rest position, tensioning means operatively connected to said pulley-driving means and operable in response to starting said pulley driving means to increase the spacing between said pulleys, said tensioning means including pressure fluid operable cylinder piston means having an element thereof connected to one of said pulleys, said tensioning means having associated therewith link means positively determining the rest position of said control means automatically, said linlt means being operatively connected directly to that one element which is operatively connected to said one pulley, longitudinally displaceable guiding means for feeding the enveloping fabric to said pulley, the guiding means comprising two rotatably journaled guiding rollers adapted to receive therebetween the enveloping fabric, and braking means operable to brake one of said guiding rollers for stress variation 2 An apparatus in combination according to claim 1, which includes means for permitting rotation of said guiding rollers in one direction only while preventing rotation in the opposite direction 3. An apparatus in combination according to claim 1, which includes longitudinally displaceable frame means supporting said guiding rollers, and a fluid-pressure-operable cylinderpiston system for actuating said last-mentioned frame means.

4. An apparatus in combination according to claim 2, which includes a movable cutting knife arranged between the guiding device and the pulley adjacent thereto, said cutting knife having a length corresponding at least to the width of the enveloping fabric to be applied to the belt.

5. An apparatus in combination according to claim 4, in which the cutting knife is operable to occupy an angle considerably in excess of with regard to the longitudinal edges of the enveloping fabric.

6. An apparatus in combination according to claim 4, which includes rotatably journaled lever means and also includes pressure-fluid-operable cylinder-piston means for actuating said lever means, said cutting knife being arranged at the free end of said lever means.

7. An apparatus in combination according to claim 1, which includes folding roller heads, and in which said profiled rollers are detachably arranged in said folding roller heads 

2. An apparatus in combination according to claim 1, which includes means for permitting rotation of said guiding rollers in one direction only while preventing rotation in the opposite direction.
 3. An apparatus in combination according to claim 1, which includes longitudinally disPlaceable frame means supporting said guiding rollers, and a fluid-pressure-operable cylinder-piston system for actuating said last-mentioned frame means.
 4. An apparatus in combination according to claim 2, which includes a movable cutting knife arranged between the guiding device and the pulley adjacent thereto, said cutting knife having a length corresponding at least to the width of the enveloping fabric to be applied to the belt.
 5. An apparatus in combination according to claim 4, in which the cutting knife is operable to occupy an angle considerably in excess of 90* with regard to the longitudinal edges of the enveloping fabric.
 6. An apparatus in combination according to claim 4, which includes rotatably journaled lever means and also includes pressure-fluid-operable cylinder-piston means for actuating said lever means, said cutting knife being arranged at the free end of said lever means.
 7. An apparatus in combination according to claim 1, which includes folding roller heads, and in which said profiled rollers are detachably arranged in said folding roller heads. 